856 HEIDENHAIN Technical Manual MANUALplus 620
The step response illustrated above is idealized. In practice, interfering 
oscillations are superimposed on the step response.
You can reduce these interference oscillations with the differential factor, the 
PT
2
 second-order time-delay element, the band rejection filter and the low-
pass filter of the speed controller.
Differential factor The differential factor reduces low-frequency oscillations. However, it 
increases the tendency to oscillate in the high frequency range.
 In MP_vCtrlDiffGain, enter a differential factor.
Estimating the differential factor:
MP_vCtrlDiffGain: Differential factor of the speed controller [As
2
]
MP_vCtrlPropGain: Proportional factor of the speed controller
T: Period duration of the lowest disturbance frequency [s]
MP_vCtrlDiffGain
Differential factor of the speed controller 
Available from NCK software version: 597 110-01.
Format: Numerical value 
Input: 0.000 000 000 to 1 [As
2
/rev.]
Default: 0 [As
2
/rev.]
Access: LEVEL3
Reaction: RUN
Ensure that the system is stable enough!
The differential factor is not recommended on machines with motors that 
have belt couplings. The influence of aging and temperature is too great.
MP_vCtrlDiffGain
T MP_vCtrlPropGain⋅
8
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